Use audio_module_handle_t and audio_patch_handle_t consistently

Bug: 27814144
Change-Id: I54b7a73ec318779fd3addb060998f4d94141152d
diff --git a/services/audiopolicy/service/AudioPolicyClientImpl.cpp b/services/audiopolicy/service/AudioPolicyClientImpl.cpp
index 08f9cc1..dbcc070 100644
--- a/services/audiopolicy/service/AudioPolicyClientImpl.cpp
+++ b/services/audiopolicy/service/AudioPolicyClientImpl.cpp
@@ -30,7 +30,7 @@
     sp<IAudioFlinger> af = AudioSystem::get_audio_flinger();
     if (af == 0) {
         ALOGW("%s: could not get AudioFlinger", __func__);
-        return 0;
+        return AUDIO_MODULE_HANDLE_NONE;
     }
 
     return af->loadHwModule(name);